Iron (Fe) and manganese (Mn) are essential metals; however, both deficiency and excess amounts can result in health abnormalities. In adults, the brain is a critical target organ of Mn toxicity, with overexposure leading to Parkinson's-like symptoms. Virtually nothing is known about excess Mn during development. Iron deficiency (ID) enhances brain Mn accumulation and toxicity. Since the brain continues to develop throughout childhood, disturbances in the proper development of the brain during this period can have long-term consequences on brain function. Rats will be fed either control; low Fe; high Mn; or low Fe + high Mn diets throughout pregnancy and lactation. To determine whether Mn accumulation plays a role in the consequences of ID during development: the relationship between blood Fe status and brain Mn accumulation will be evaluated by neutron activation analysis; proteins involved in Fe and Mn transport will be assessed by western blot analysis; neurochemical effects will be characterized by measuring glutamate and GABA levels via HPLC. [unreadable] [unreadable]